JPH0455220B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to thermoplastic molding compositions, in particular by incorporating linear low density polyethylene and glass fibers into moldable thermoplastic polyester, copolyester or poly-blend compositions. It provides a composition with improved impact strength. More specifically, the invention provides (a) 30 to 92% by weight of (1) polyethylene terephthalate, or (2) polybutylene terephthalate, or (3) a copolyester of (1) and (2), or (4 ) Above (1)
A mixture of any two or more of the compounds of ~(3), (b)3~
20% by weight linear low density polyethylene and (c) 5~
Concerning a composition comprising 50% by weight of glass fibers. The compositions of the present invention may further include an effective amount of mica filler to strengthen and/or reduce deformation. BACKGROUND OF THE INVENTION High molecular weight linear polyesters and copolyesters consisting of glycols and terephthalic acid or isophthalic acid have recently become available for production. Methods for making polyesters are described in Whinfield et al., US Pat. No. 2,465,319 and Pengilly, US Pat. No. 3,047,539, which are incorporated herein by reference. These patents state that the polyesters are particularly suitable for film or fiber production. With the development of molecular weight control, the use of nucleating agents and two-step molding cycles, poly(ethylene terephthalate) has become an important component of injection molding compositions. Additionally, poly(1,4-butylene terephthalate) is particularly useful as a component in injection molding compositions because it crystallizes very rapidly from the melt. Workpieces molded from such polyester have superior surface hardness and abrasion resistance, gloss, and low surface friction compared to other thermoplastic resins. Furthermore, poly(1,4-butylene terephthalate) can be molded more easily than poly(ethylene terephthalate), especially when used for injection molding applications. For example, poly(1,4-
butylene terephthalate) can be injection molded into highly crystalline, dimensionally stable molded articles within short cycle times at low molding temperatures of about 30 to about 60°C. Even at low molding temperatures, the crystallization rate is fast, so there is no difficulty in removing the molded product from the mold. Moreover, the dimensional stability of poly(1,4-butylene terephthalate) injection molded articles is consistently excellent even at temperatures near or slightly above the glass transition temperature of poly(1,4-butylene terephthalate). Coinciding with the development of injection molding of polyester resins, glass fiber reinforced compositions also became available.
See, for example, U.S. Pat. No. 3,368,995 by Fukukawa et al.
See US Pat. No. 3,814,725 to Zimmerman. These injection molding compositions have all the benefits of unfilled polyester, and the glass reinforcement provides higher molded article stiffness, yield strength, modulus and impact strength. Stable polyblends of poly(1,4-butylene terephthalate) and poly(ethylene terephthalate) can also be formed into useful unreinforced and reinforced products. Reference may be made to US Pat. No. 3,953,394 by Fox and Wambach, which is incorporated herein by reference. Furthermore, copolyesters and block copolyesters containing units derived primarily from poly(1,4-butylene terephthalate) and aromatic/aliphatic or aliphatic polyesters are known. Reference may be made to now abandoned US patent application Ser. No. 752,325, filed December 20, 1976, which is incorporated herein by reference. These copolyesters and block copolyesters are useful as molding resins, as are intimate mixtures with poly(1,4-butylene terephthalate) and/or poly(ethylene terephthalate). These compositions are said to have increased impact strength. It is also known to add polyolefins, especially high-pressure low-density polyethylene and high-pressure high-density polyethylene, to improve the quality of thermoplastic resins or to make them have specific physical properties. For example, US Pat. No. 3,405,198 to Rein et al. describes the use of polyethylene as an impact modifier in poly(ethylene terephthal). Also, US patent no.
No. 4122061 discloses poly(1,4-butylene terephthalate) resin, poly(ethylene terephthalate) resin, glass fiber reinforcement (which may be used alone or in combination with a mineral filler). Polyester compositions are described containing copolymer resins as impact modifiers based on polyolefins, or olefin-based impact modifiers containing polyethylene and propylene-ethylene copolymers. U.S. Pat. No. 4,185,047 to Cohen et al. describes thermoplastic polyester compositions, particularly poly(ethylene terephthalate) and
The use of high-pressure low-density polyethylene in (butylene terephthalate) to improve mold release properties is described. All of the above patents are cited by reference in this invention. Additionally, it has recently been shown that the addition of linear low density polyethylene to aromatic polycarbonate results in areas of increased thickness when compared to control samples of regular polycarbonate or polycarbonate blends with commercially available polyethylene. It has been discovered that molding compositions can be obtained that have improved weld line strength and thermal stability while retaining excellent impact strength. For example, see page 309 of Research Disclosure #20819, August 1981. Furthermore, low-density polyethylene,
Compositions consisting of thermoplastic polyesters or polyester blends and impact-modified polyester-polycarbonate blends are known,
Improved miscibility, weld line strength, flow properties, and mold release, respectively, and reduced plateout. The above references are also cited in the present invention. In the present invention, a small amount of linear low density polyethylene, about 3 to about 20% by weight, preferably about 5 to about 15% by weight, and about 5 to about 50% by weight of glass fibers are added to a thermoplastic polyester. It has been found that the impact strength of thermoplastic polyester compositions is significantly improved by incorporating them into the composition. The impact strength of the compositions of the present invention is significantly improved over thermoplastic polyester compositions containing high pressure processed low density polyethylene and/or glass. Although the exact mechanism by which this significant improvement in impact strength is achieved is not clear, it is clear to those skilled in the art that such improvement is achieved due to the amount of linear It will be appreciated that it is a synergistic effect of low density polyethylene and glass fiber. The present invention provides improved impact resistant thermoplastics useful for molding or extrusion, such as injection molding, injection blow molding, compression molding, transfer molding, extrusion molding, sheet extrusion, wire coating, extrusion blow molding, etc. A composition is provided. The composition of the present invention comprises (a) essentially poly(ethylene terephthalate);
( b) 5 to 50% by weight of glass fibers, alone or in combination with an effective amount of reinforcing filler; and (c) 3 to 20% by weight of linear low density polyethylene. More particularly, the compositions of the present invention contain (a) 30 to 92% by weight of () poly(1,4-butylene terephthalate), () essentially terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, of the formula (wherein, X represents an alkylene or alkylidene of 1 to 4 carbon atoms, carbonyl, sulfonyl, oxygen or two benzene rings directly bonded), and a compound having 6 to 12 carbon atoms in the chain. One or more dicarboxylic acids selected from the group consisting of aliphatic dicarboxylic acids having carbon atoms, and linear or branched divalent aliphatic acids having 2 to 10 carbon atoms in the chain. or an aliphatic/aromatic copolyester derived from one or more alicyclic glycols, a terminal reactive block of () (), and a terminal reactive block of copolyester (). block copolyesters, in which case the copolyester () has at least 10% of aliphatic units derived from dicarboxylic acids or linear aliphatic or aliphatic glycol terminal-reactive aliphatic polyesters; However, the above blocks are connected by an end-to-end bond. () poly(ethylene terephthalate), () an aromatic polycarbonate, preferably bisphenol-A, or () a combination thereof, (b) 5 to 50% by weight of glass fiber, and (c) about 3 to about 20% by weight. Preferably the composition comprises 5 to 15% by weight, most preferably 5 to 1% by weight of linear low density polyethylene. The compositions of the present invention may further contain sufficient amounts of mica or clay to reduce deformation and/or talc to improve electrical properties. Additionally, the compositions of the present invention contain impact modifiers such as, but not limited to, core-shell type acrylic elastomers, ethylene-vinyl acetate copolymers, and ethylene-ethyl acrylate copolymers. It may be additionally contained. Furthermore, the composition of the present invention may contain one or more of the following additives. That is, they include mold release agents, flame retardants, colorants, nucleating agents, stabilizers, fillers, flow promoters, and the like. DETAILED DESCRIPTION OF THE INVENTION The high molecular weight polyesters used in the practice of this invention are polyhydric glycol esters of terephthalic acid and isophthalic acid. these are,
It is widely available commercially. For example, the trade name of General Electric Company (located in Pickfield, Mass.)
Poly(1,4-
butylene terephthalate) and Goodyear
Trade name VITUF from Tire and Rubber Company
Poly(ethylene terephthalate) is commercially available as These high molecular weight polyesters can also be readily produced by known techniques, for example by transesterifying esters of terephthalic acid and/or isophthalic acid with glycols followed by polymerization, or by converting glycols into free acids or their It can be produced by heating with a halide derivative. These manufacturing methods are described in U.S. Patent No.
Also described in No. 2465319 and No. 3047539, among others. The glycol portion of the polyester contains 2 to 10 carbon atoms, preferably 2 to 4 carbon atoms in the form of linear methylene chains. Preferably, the general formula high molecular weight polymeric glycol terephthalates or isophthalates having repeating units of (wherein n is 2 to 4), mixtures of such esters, and colloids of terephthalic acid and isophthalic acid with up to 30 mol % of isophthalic units. There are polyesters such as polyester. Particularly preferred polyesters are poly(ethylene terephthalate) and poly(1,4-butylene terephthalate). In the specific example, poly(1,4-butylene terephthalate) is mainly shown, but when poly(1,4-butylene terephthalate) is used for injection molding, poly(ethylene terephthalate) is sometimes required. This is because it crystallizes at a fast rate without the need for nucleating agents or long cycling processes. To further illustrate, high molecular weight polyesters, such as poly(1,4-butylene terephthalate), have a molecular weight of at least 0.7 dl/g, preferably 0.8 dl, when measured in a 60:40 phenol-tetrachloroethane mixture at 30°C. /g or more.
When the intrinsic viscosity is 1.0 dl/or more, the toughness of the composition of the present invention is further improved. Copolyesters useful in the compositions of the present invention preferably contain terephthalic acid, isophthalic acid or reactive derivatives thereof, or any combination thereof, and linear or branched aliphatic and/or cycloaliphatic Can be manufactured from glycol. Specifically, glycols include ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
These include 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or a mixture of any of the above.
Additionally, other dicarboxylic acids useful for the acid component of the copolyester include, but are not limited to, aromatic dicarboxylic acids such as naphthalene dicarboxylic acid; (In the formula, X represents an alkylene group or alkylidene group of 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, oxygen, etc., or a direct bond of two benzene rings.), and suberic acid, sebacic acid Included are aliphatic dicarboxylic acids having 6 to 12 carbon atoms, including , azelaic acid, adipic acid, and the like. The above copolyesters can be produced by transesterification by conventional methods. These copolyesters are preferably derived from 50% or more poly(1,4-butylene terephthalate) units. Block copolyesters useful for the compositions of this invention include () terminal-reactive poly(1,4-
butylene terephthalate), preferably of low molecular weight, and () a terminal-reactive copolyester as described above or () a terminal-reactive aliphatic polyester or a combination of any of these. It is something. The terminal group is a hydroxyl group, a carboxyl group, a carbalkoxy group, and also includes reactive derivatives thereof. Generally, these block copolyesters can be prepared by reacting the terminal reactive units described above in the presence of a transesterification catalyst such as zinc acetate, manganese acetate, titanium ester, and the like. After mixing, polymerization is carried out under standard conditions.
Polymerization under high vacuum, such as at 220 DEG to 280 DEG C. and 0.1 to 2 mm of mercury, produces block copolymers in which the distribution of chain segments is minimally randomized. These block copolyesters are described in now abandoned US patent application Ser. No. 752,325, filed December 20, 1976, which is incorporated herein by reference. The copolyester units () preferably have a molar concentration of aliphatic glycol, aromatic acid and aliphatic acid of from 1:9 to 9:1, particularly preferably from 3:7 to
7:3 mixture of aromatic and aliphatic dibasic acids. Further, the terminal-reactive aliphatic polyester unit () preferably has a hydroxy-containing terminal group, but may contain substantially stoichiometric amounts of aliphatic diol and aliphatic dicarboxylic acid. . Both aromatic/aliphatic copolyesters () and aliphatic polyesters () can be readily produced by known methods and are commercially available. These materials are sold, for example, at the Ruco in Hicksville, New York.
It is sold under the trade name "Rucoflex" by DiVision/Hooker Chemical Company. Block copolyesters useful in the present invention preferably contain 95 to 50% by weight poly(1,4-
butylene terephthalate). These poly(1,4-butylene terephthalate) blocks prior to incorporation into the block copolyester, when measured in 60:40 phenol-tetrachloroethane at 30°C:
Preferably 0.1 dl/g or more, more preferably
It is desirable to have an intrinsic viscosity of 0.1 to 0.5 dl/g. The remainder, ie 5 to 50% by weight, of the block copolyester consists of the copolyesters () and aliphatic polyesters () mentioned above. As will be apparent to those skilled in the art of the present invention, poly(1,4-butylene terephthalate) blocks may be linear or branched, e.g. containing three or more ester-forming groups. Branched chains can be obtained by using the contained branched components. These branched components include, for example, polyols such as pentaerythritol and trimethylolpropane, and polybasic acid compounds such as trimethyl trimesitide. For branched poly(1,4-butylene terephthalate) resins and methods for their preparation, see Borman, incorporated herein by reference.
No. 3,953,404. Also useful in the present invention are high molecular weight aromatic polycarbonates and blends of polycarbonates and poly(ethylene terephthalate) and/or poly(1,4-butylene terephthalate) resins as described above. The aromatic polycarbonate resin useful in the present invention may be any known aromatic polycarbonate resin. Generally, the polycarbonates can be made by reacting dihydric phenols with carbonate precursors such as phosgene, halogenated formates or carbonates. These polycarbonate polymers have the formula (In the formula, A is a divalent aromatic group of divalent phenol used in the polymer production reaction.) It can be represented by a repeating unit. A "high molecular weight" aromatic polycarbonate polymer is a polycarbonate having an intrinsic viscosity (dl/g as measured in methylene chloride at 25°C) of about 0.30 or greater. The dihydric phenols that can be used to prepare aromatic carbonate polymers contain two hydroxyl groups as functional groups, each hydroxyl group being a monomer bonded directly to a carbon atom of the aromatic nucleus. It is a nuclear or polynuclear aromatic compound. Representative divalent phenols include 2,5-bis-(4-hydroxyphenyl)propane, 2,
2-bis-(4-hydroxyphenyl)pentane,
2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)propane,
2,2-bis-(4-hydroxy-3,5-dibromophenyl)propane, 1,1-bis-(4-
hydroxyphenyl)ethane, and 4,4-dihydroxy-3,3-dichlorodiphenyl ether. Other dihydric phenols that can be used to prepare the aromatic carbonate polymers mentioned above are described in the patent application filed by the Applicant of the present invention, which is cited by reference in this invention.
Goldberg, US Pat. No. 2,993,835. The dihydric phenol most preferably used is 2,2-bis-(4-hydroxyphenyl)propane. If a polycarbonate polymer is preferred rather than a homopolymer, it will be appreciated that two or more dihydric phenols or one dihydric phenol and a glycol, hydroxy or acid terminated polyester or dibasic acid It can also be used in combination with Thus, in the present invention, the term polycarbonate resin is understood to include polycarbonate copolymers within this range. The present invention also includes blends of poly(ethylene terephthalate), poly(1,4-butylene terephthalate), copolyesters and/or block copolyesters and/or derivatives thereof, aromatic polycarbonates, or combinations thereof. can also be used. In the present invention, in order to significantly improve the impact resistance of any one of the above-mentioned polymers or a combination thereof, glass fibers and 3 to
It has been found that it is necessary to contain 20% by weight, preferably 5 to 15% by weight, of linear low density polyethylene. Linear low density polyethylenes useful in the present invention are well known materials, such as Exxon's Escorene
(trade name) or G resin from Union Carbide Company. In addition, these are cited as references in the present invention, such as U.S. Pat. No. 4,354,009 and U.S. Pat.
(Published October 17, 1979) and U.S. Patent No. 4128607
They can also be easily produced by polymerization methods such as those described in this issue. These linear low density polymers range from about 0.89 to about
0.9 g/cc, preferably about 0.915 to about 0.945 g/cc
It is better to have a density of These linear low density polyethylene polymers actually contain ethylene and a small amount, i.e. up to 20 mol%, preferably 15
There are copolymers with α-olefins of 3 to 15 carbon atoms up to mol %. The α-olefin preferably has 3 to 10 carbon atoms, most preferably 4 to 8 carbon atoms. These linear low density polyethylenes can be distinguished from high pressure low density polyethylenes and high density polyethylenes produced from coordination catalyst systems. Polyethylene produced by high pressure method is
It is substantially free of side chain branching and contains limited concentrations of simple to random branching. Preferred linear low density polyethylene copolymers include ethylene and propylene, butene-1, pentyne-1,4-methylpentene-1, hexene-1,
and one or more alpha-olefins selected from the group consisting of butene-1 and octene-1, most preferably butene-1 and octene-1. A polymer having a desired density can be obtained by adjusting the copolymerization rate of α-olefin and the formation characteristics of the polymer during copolymerization. Adding a large amount of comonomer to this copolymer can reduce the density of the copolymer. Typically, the copolymerization of linear low density polyethylene is carried out in either a gas phase fluidized bed reactor or a liquid phase solution process reactor, preferably in the latter,
Under pressure ranging from normal pressure to 5000psi, preferably
Below 1000psi, 20~310℃, preferably 30~115
C. in the presence of a suitable highly active catalyst. Typical catalyst systems are transition metal complex catalysts, preferably one or more compounds of these metals with a halogen or hydrocarbon group bonded to a transition element of the periodic table a, a and a, and a metal halogen. Chemicals include compounds with metals directly bonded to carbon;
For example, it consists of a transition metal complex catalyst consisting of a reducing component such as a metal alkyl. Particularly preferred catalyst systems are those with titanium halides and where the effective organometallic component is a metal alkyl compound with aluminum as metal, especially LiAl(hydrocarbon) ₄ . Such catalyst systems include, for example, TiCl ₄ −LiAl(alkyl) ₄ , VOCl ₃ −
Li (alkyl), MoCl ₃ −Al (alkyl) ₃ , TiCl ₄ −
Includes alkyl MgBr etc. These similarly useful catalyst systems are U.S. Pat. No. 4,354,009;
No. 4,076,698, European Application No. 4,645 and US Pat. No. 4,128,607, cited above. Such a catalyst system has a molar ratio of ethylene to catalyst.
Used in the range of 35,000 to 400,000:1. Preferred linear low density polyethylene lene copolymers thus prepared have an unsaturation content of less than 1, preferably from about 0.1 to about 0.3 C=C/1000 carbon atoms, and less than about 3% by weight; Preferably n-hexane extractable component content of 2% by weight or less (50°C
). A preferred method for producing linear low-density polyethylene copolymers is described in Chem.Eng., 1979, cited by reference in this invention.
It can be produced by the Unipol method described in December/March issue, pages 80-85. The compositions of the invention must also contain glass fibers. Fibrous glass may be untreated, but may be treated, preferably with a silane or titanate coupling agent. Filamentary glasses are well known in the art and are available from a variety of manufacturers. When the composition of the present invention is ultimately used in electrical applications, it is preferred to use soda-free lime-aluminum borosilicate glass as the fibrous glass filament. This is usually E
- known as a class. Lower grade soda glasses, such as those known as C class, can also be used if electrical properties are not particularly important. Most preferred are E class G filaments, preferably smaller in diameter than K filaments. Filaments can be manufactured by conventional methods such as fluid or air blowing, flame blowing, and mechanical stretching. Preferred filaments for plastic reinforcement are those produced by mechanical tension. The length of the gas filament and whether the filament is bound into fibers, whether the fibers are bound into yarns, ropes, rovings, or woven into mats are relevant to the present invention. not important. However, in the production of molding compositions it is convenient to use filamentary glass in the form of chopped strands, 1/8 to 2 inches long. However, shorter lengths of glass fibers are present in articles molded from the compositions of the present invention because significant fragmentation occurs during compounding. However, thermoplastic injection molded products with filament lengths between 0.0005 and 0.125 inches exhibit the best physical properties. The compositions of the present invention may further optionally contain effective amounts of any of the known impact modifiers useful for polyesters and polyester blends, including polycarbonates. Preferred impact modifiers usually consist of acrylic or methacrylic grafted polymers of conjugated dienes or acrylic ester elastomers (alone or copolymerized with aromatic vinyl compounds). A particularly preferred grafted polymer is Rohm &Haas'
Acryloid KM653 (product name), Acryloid KM330
(trade name) and Acryloid KM611 (trade name). Typically, these impact modifiers contain units derived from butadiene or isoprene, alone or in combination with a vinyl aromatic compound, or from isoprene, alone or in combination with a vinyl aromatic compound. The above-mentioned impact modifiers are disclosed in U.S. Pat. No. 4,180,494 by Fromuth et al. and U.S. Pat.
No. 3808180, US Patent No. 3808180, Farnham et al.
4096202 and U.S. Patent No. 4096202 and Cohen et al.
It is described in No. 4260639. The most preferred impact modifier is a two-stage impact modifier having a rubbery core based on either butadiene or n-butyl acrylate and a second stage polymerized from methyl methacrylate alone or in combination with styrene. It is made of polymer. Also present during the first stage are crosslinking and grafting monomers. Examples of crosslinking monomers include 1,3-butylene diacrylate, divinylbenzene and butylene dimethacrylate. Examples of grafting monomers are allyl acrylate, allyl methacrylate and diallyl maleate. Preferred impact modifiers include U.S. Pat.
It is also described in No. 4292233. These impact modifiers consist of a fairly high content of a cross-linked butadiene polymer grafted base with grafted acrylonitrile and styrene. Other preferred impact modifiers include, but are not limited to, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, and the like. The compositions of the present invention can be made flame retardant by using effective amounts of conventional flame retardants. As is well known, flame retardants are based on red phosphorus, phosphorus compounds, halogens and nitrogen compounds, alone or in combination with synergists such as antimony compounds. Particularly useful is
Cited as a reference in the present invention
Polymeric and oligomeric flame retardants consisting of tetrabromobisphenol-A carbonate units listed in U.S. Pat. No. 3,833,685 to Wambach. The compositions of the present invention may further contain fillers, such as, but not limited to, effective amounts of mica or clay as reinforcing and anti-deformation agents and talc to improve electrical properties. It may also contain. Finally, the compositions of the invention may also contain an effective amount of one or more of the additives listed below. i.e. flow promoters, nucleating agents, colorants, stabilizers,
Coupling agents, etc. The proportions of the components of the compositions of the invention can vary widely depending on the number of components, the specific components used, the properties required and the end use of the plastics produced using the compositions. usually,
The compositions of the present invention are based on the weight percent of the final composition:
30 to 92% of one type of thermoplastic polyester resin or a mixture of two or more types of thermoplastic polyester resins, 3 to 20% of linear low density polyethylene, and 5 to 92% of linear low density polyethylene.
50% glass fiber. Preferably, the composition of the present invention comprises 30-80% of said polyester, 5-15% of linear low density polyethylene and 15-80% of said polyester.
35% glass fiber. Further, the thermoplastic polyester resin includes 0 to 100% poly(ethylene terephthalate), 0 to 100% poly(1,4-butylene terephthalate), and 0 to 100% poly(1,4-butylene terephthalate).
Consists of 100% aromatic polycarbonate or a combination of these to make a total of 100%.
0 to 0 for reinforcement and prevention of deformation as desired.
It may also contain 40% by weight of mica or clay, or 0 to 40% by weight of talc to improve electrical properties. Additionally, the compositions of the invention may contain up to 25%, preferably from 5 to 25%, of impact modifiers. The compositions of the invention can be manufactured by conventional methods. For example, in one method, linear low density polyethylene and glass fibers are placed in an extrusion compound with a thermoplastic polyester resin to produce moldable pellets. In this way, linear low density polyethylene and glass fibers are branched into a matrix of thermoplastic polyester. In another method, linear low density polyethylene and glass fibers are mixed with thermoplastic polyester by dry-blending and then melted on a mill or comminuted or extruded into chops. Alternatively, the components are powdered or mixed with the granular thermoplastic resin and then molded, for example by injection or transfer molding techniques. Generally, it is important that these components contain as little moisture as possible. However, it has recently become clear that polyester molding compositions may be produced with a small moisture content. Cited as references in this invention,
See US Pat. No. 4,351,758 to Lu et al. Furthermore, the formulation of the composition is such that the residence time in the machine is short, the temperature can be carefully regulated, frictional heat is utilized, or the additives and thermoplastic are intimately mixed. It must be carried out in such a way that blending is achieved. Although not required, best results are obtained if the ingredients are premixed and pelletized before molding. Pre-formulation can be carried out using conventional equipment. For example, if the thermoplastic polyester is carefully pre-dried, for example at 125°C for 4 hours, then linear low density polyethylene and glass fibers and additives are used, all of which is fed into a single screw extruder. .
The single screw extruder used in this case is
It is equipped with a long transition section and a metering section to ensure complete melting. Also, for example, 28
A twin-screw extruder, such as a Warner Pfleiderer machine of 1.5 mm, may be fed with resin, linear low density polyethylene, and glass fibers from a feed section. In both cases, the machine temperature is usually 450-570〓
is appropriate. The preformulated composition can be formed into a molding compound such as conventional particles, pellets, etc. by conventional extrusion techniques. The compositions of the present invention can be molded using any conventional equipment for thermoplastic compositions. For example, for poly(1,4-butylene terephthalate) based compositions, e.g.
In a Nowbury type extruder, e.g.
Excellent molding can be carried out by injection molding machines at conventional cylinder temperatures of, for example, 150 °C, and also at conventional molding temperatures of, for example, 150 °C. On the other hand, for poly(ethylene terephthalate)-based compositions, the non-uniform crystallization of the inside and outside of thick molded parts makes use of well-known but somewhat unconventional techniques. For example LiOH, sodium stearate, graphite, ZnO or
By containing a nucleating agent such as a metal oxide such as MgO, it can be molded at a conventional molding temperature of 180°C or higher. In order to provide a better understanding of how the invention may be carried out, the following examples are given by way of illustration and are not to be construed as limiting in any way. Examples 1-7 and Comparative Examples 1-4 Poly(1,4-butylene terephthalate) resin, glass, and linear low density polyethylene were prepared and extruded from a single screw extruder at 500-550 mm. For comparison, poly(1,4-butylene terephthalate) and linear low-density polyethylene, and separately from this, a mixture of poly(1,4-butylene terephthalate) and glass were also extruded in the same manner.
The extrudates were pelletized and injection molded on a 490° VanDorn molding machine at a molding temperature of 150°. The composition and physical properties are shown in Table 1.

[Table] As is clear from the results shown in Table 1, when only linear low density polyethylene is added to poly(1,4-butylene terephthalate), there is almost no effect on the physical properties obtained. (Comparative Examples 1 to 3).
Additionally, the addition of glass fibers to poly(1,4-butylene terephthalate) improves notched isot impact strength, as is well known in the art. (Comparative Example 4) However, when both glass fiber and linear low density polyethylene are added to poly(1,4-butylene terephthalate), the notched isot impact strength is significantly improved more than expected. (Examples 1 to 7) The impact strength without notches in Examples 2 to 4 corresponding to the present invention was clearly improved when compared with the glass reinforced poly(1,4-butylene terephthalate) of Comparative Example 4. has been done. Finally, as is clear from Examples 1 to 7 in Table 1, the effect of improving impact resistance is not limited to only one type of linear low density polyethylene; There is no difference even at a content as low as 7% by weight. Moreover, as shown in these examples, even if the melt index of linear low density polyethylene is varied over a wide range within the same type, there is little change in the effect of improved impact strength achieved. There is no. Examples 8 to 14 (including Comparative Examples 5 to 6) Poly(1,4-butylene terephthalate), glass, linear low density polyethylene and polycarbonate or polyethylene were prepared by the methods described in Examples 1 to 7. (ethylene terephthalate) or a dry blend of both. Specific compositions and their physical properties are shown in Table 2.

[Table] Again, as is clear from Comparative Example 5 and Example 8, the impact resistance of reinforced poly(1,4-butylene terephthalate) is greatly improved when linear low-density polyethylene is included. Ru. Furthermore, as is clear from Comparative Example 6 and Examples 9 to 14, glass-reinforced polyester blends of poly(1,4-butylene terephthalate) and polycarbonate, or poly(1,4-butylene terephthalate), polycarbonate, and poly(ethylene terephthalate) ) Glass-reinforced polyester blends containing both linear low-density polyethylene of 1% or more will greatly increase impact resistance regardless of whether it is added at a high or low content. Reference Examples 15-22 Glass-reinforced polyblends of filled and unfilled poly(1,4-butylene terephthalate) and poly(ethylene terephthalate) or aromatic polycarbonate were prepared in the same manner as Examples 1-7. and a specified amount of an additional impact modifier consisting of linear low density polyethylene alone or with either ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer or core-shell type acrylic elastomer. A dry blend was prepared containing the following: The compositions and their physical properties are shown in Table 3.

【table】

TABLE Once again, the impact resistance of the polyblend composition was improved by including linear low density polyethylene in the composition. This also applies to filled compositions to which mica is added to prevent deformation. Although the addition of mica to the composition reduces the impact strength (compare Reference Examples 15 and 18), excellent impact strength is still achieved. (Reference examples 15 to 17). Furthermore, reference examples 16 and 19, reference examples 17 and 20, reference examples
21 and 22, for the composition ethylene-ethyl acrylate copolymer, ethylene-
The improved impact strength achieved with linear low-density polyethylene was achieved by adding vinyl acetate copolymer, and core-shell acrylate elastomer (KM330), respectively, or replacing a portion or amount of linear low-density polyethylene. can be maintained. Reference Examples 23 to 28 In the same manner as Examples 1 to 7, compositions containing added mica fillers containing talc or a flame retardant to further improve electrical properties were produced. The composition and physical properties are shown in Table 4.

【table】

[Table] Reference Examples 23 to 28 improve electrical properties for mica-filled, glass-reinforced polyblends containing moderate amounts of linear low-density polyethylene and high content of poly(ethylene terephthalate). This shows that even when talc is added in the varying amounts shown in Table 4, excellent impact strength is maintained. Furthermore, Reference Examples 27 and 28 show that the flame-retardant compositions of the present invention can similarly maintain excellent impact strength. It will be appreciated that other modifications and variations of the present invention are possible within the scope of the above technology. Such obvious modifications that may be made in the specific embodiments as described above are intended to be included within the full scope of the invention as defined by the appended claims.

Claims (1)

[Scope of Claims] 1. In a thermoplastic molding composition, the following components (a) 30 to 92% by weight of (1) polyethylene terephthalate or (2) polybutylene terephthalate or (3) (1) and copolyester of (2) or (4) a mixture of any two or more of the above compounds; (b) 3 to 20% by weight of linear low density polyethylene having a density of 0.89 to 0.96 g/cc; and (c ) A thermoplastic molding composition with improved impact resistance, characterized in that it consists of 5 to 50% by weight of glass fibers. 2. The composition according to claim 1, wherein component (a) is polyethylene terephthalate. 3. The composition according to claim 1, wherein component (a) is polybutylene terephthalate. 4. The composition according to claim 1, wherein component (a) is a copolyester of polyethylene terephthalate and polybutylene terephthalate. 5. The composition of claim 4, wherein the copolyester is a random copolyester. 6. The composition of claim 4, wherein the copolyester is a block copolyester. 7. The composition according to claim 1, wherein component (a) is a mixture of polyethylene terephthalate and polybutylene terephthalate. 8. The composition of claim 1, wherein component (b) is linear low density polyethylene having a density of 0.915 to 0.945 g/cc. 9. A composition according to claim 1, wherein component (b) is a copolymer derived from ethylene and a small amount of an alpha-olefin having from 3 to 10 carbon atoms. 10. The composition of claim 9, wherein component (b) is a copolymer derived from ethylene and a small amount of alpha-olefin having from 4 to 8 carbon atoms. 11. The composition of claim 9, wherein the linear low density polyethylene copolymer is a copolymer derived from ethylene and butene-1. 12. The composition of claim 9, wherein the linear low density polyethylene copolymer is a copolymer derived from ethylene and octene-1. 13. The composition according to claim 1, wherein component (b) is 5 to 15% by weight.